Compositions containing quaternary ammonium salts or imidazolinium compounds having at least one long chain hydrocarbyl group are commonly used to provide fabric softening benefits when used in a laundry rinse operation. Numerous patents have been issued for these types of compounds and compositions.
More recently, however, in view of concerns for the environmental safety (e.g., biodegradability) of the quaternary compound softeners, as well as limits in the amounts of these cationic compounds which can be stably incorporated into the more convenient to use liquid formulations, there have been many proposals for partial or total replacements of the conventional "quat" fabric softeners which are exemplified by dimethyl distearyl (or ditallow) ammonium chloride and various imidazolinium compounds.
For instance in GB 2,032,479A, corresponding to EP 038862, to D. Fontanesi (assigned to Albright & Wilson Ltd.) water dispersible unquaternized hydroxyalkyl diamidoamine compounds of formula EQU RNH ((CH.sub.2).sub.n NR).sub.m R
wherein an average of from 20% to 80% of the R groups are C.sub.12 to C.sub.22 acyl, at least 20% of the R groups are --CH.sub.2 CH.sub.2 OH or --CH.sub.2 CHOHCH.sub.3 or mixtures of these groups, and any other R group is hydrogen, n is 2 or 3 and m is an integer of from 2 to 5, are provided as mobile pastes in the presence of lower alkanol solvents. This is stated to be in contrast to partially neutralized unquaternized diamidoamines which, while providing highly effective fabric softening properties, are too viscous even when diluted in the lower alkanol solvents for convenient handling.
U.S. Pat. No. 5,154,838 (corresponding to EP 0459211A2) to Yomamura, et al. (assigned to Kao Corp.) discloses an aqueous liquid softener composition based on an amidoamine compound which is the condensation reaction product of a di- or tri-amine of formula (I): EQU R.sup.1 HN(C.sub.m H.sub.2m NH).sub.n H (I)
with a fatty acid of formula (II): ##STR1## wherein R.sup.1 represents a straight or branched chain, saturated or unsaturated hydrocarbon group having 8 to 24 carbon atoms, R.sup.2 represents a straight or branched, saturated or unsaturated hydrocarbon group having 7 to 23 carbon atoms, m represents 2 or 3, and n is 1 or 2. These compounds, which are neither hydroxylated or ethoxylated, are noted to have high dispersibility in rinse water, especially when the amidoamine compound is used in the form of its neutral salt.
U.S. Pat. No. 5,108,628 to Uphues, et al. (Henkel) discloses certain aliphatic carboxylic acid amidoamines which are obtained by reaction of polyamines (e.g., diethylentriamine, aminoethyl ethanolamine) with carboxylic acid mixtures containing ether carboxylic acids (R--O--(CH.sub.2 CH.sub.2 O).sub.n --CH.sub.2 COOH, R=C.sub.8-18 alkyl, C.sub.8-18 alkenyl or CH.sub.2 --COOH, n=2 to 20, in combination with aliphatic C.sub.8-22 monocarboxylic acids and/or amide-forming aliphatic C8-22 monocarboxylic acid derivatives) as fabric softeners stable in the presence of electrolytes.
In U.S. Pat. No. 5,133,885 to L. Contor, et al. (corresponding to EP 0423894, both assigned to Colgate-Palmolive Co., the assignee of the present invention) fabric softening compositions are described which are aqueous dispersions of a fatty acid ester quat of formula: ##STR2## where one or two R groups represent an aliphatic ester residue of from 12 to 30 carbon atoms of formula CH.sub.2n OCOR.sub.4, and the remaining R groups represent lower aliphatic, aryl or hydroxyalkyl groups, X.sup.- is an anion and "a" represents the ionic valence of the anion, and a fatty acid amidoamine softener of formula: ##STR3## where R.sup.1 is a C.sub.12 to C.sub.30 alkyl or alkenyl group, R.sup.2 represents R.sup.1, R.sup.1 CONH(CH.sub.2).sub.m or CH.sub.2 CH.sub.2 OH; R.sup.3 represents hydrogen, methyl, or (CH.sub.2 CH.sub.2 O).sub.p H, m is a number of 1 to 5 and p is a number of 1 to 5, at a weight ratio of ester quat to amidoamine of from 10:1 to 1.10. This patent discloses total amounts of esterquat and amidoamine ranging from 3% to 60% by weight, however, compositions containing at most 8% by weight of active softeners are disclosed.
U.S. Pat. No. 5,180,508 to Birkhan, et al. (corresponding to EP 0413249, assigned to REWO Chemische) discloses aqueous fabric softener rinsing agents based upon a mixture of quaternary salt compounds: a first component (a) of formula (I) ##STR4## wherein, each R is independently hydrogen or lower alkyl;
each R.sup.1 is hydrogen or an alkylcarbonyl group containing 15-23 carbon atoms, provided that at least one of R.sup.1 is an alkylcarbonyl group; PA1 each R.sup.3 is an alkyl group containing 1-4 carbon atoms which is unsubstituted or substituted with 1, 2, or 3 hydroxy groups; PA1 each R.sup.2 is an alkyl group containing 1-4 carbon atoms which may be unsubstituted or substituted with 1, 2, or 3 hydroxy groups, or is a group of the formula: ##STR5## PA1 n is 0 or 1; PA1 x and y are independently 0 or 1 with the proviso that (x+y)+(3-n)=4; and PA1 m is 1 or 2; and g is 1, 2 or 3, such that (m/g)(g)=m, and PA1 (A') an inorganic or organic acid salt of bis(hydrogenated tallow amidoethyl) hydroxyethyl amine, PA1 (B') an inorganic or organic acid salt of bis(non-hydrogenated tallow amidoethyl) hydroxyethyl amine, with the total amount of (A') and (B') being from about 2% to about 50% by weight of the composition, and the ratio by weight of (A') to (B') being in the range of from about 10:1 to abut 1.5:1, and an aqueous solvent. PA1 C.sub.14 =5% including 1% of mono-unsaturated chains (alkyl chains containing one carbon to carbon double bond, i.e. alkenyl) PA1 C.sub.16 =30% including 4% of mono-unsaturated chains. PA1 C.sub.18 =65% including 39% of mono-unsaturated chains and 1% di-unsaturated chains.
R.sup.13 is an alkyl group containing 8-22 carbon atoms; R.sup.12 is an alkyl group containing 1-4 carbon atoms which is unsubstituted or substituted with 1, 2, or 3 hydroxy groups;
R.sup.11 is hydrogen or lower alkyl;
R.sup.10 is hydrogen or alkylcarbonyl group containing 14-22 carbon atoms;
A is an anion of a quaternizing agent;
a second component (b) which is a quaternary salt of an imidazolinium compound (III), an amidoamine compound (IV), an ammonium compound (V), or diimidazolinium compound (VI). The amidoamine amine compound has the formula: ##STR6## wherein
R.sup.6.sub.1 is CHX--CHY--O;
X and Y are independently hydrogen or lower alkyl (but not both alkyl);
R.sup.7 is an alkylcarbonyl group containing 4-22 carbon atoms or H;
R.sup.9 is an alkyl group containing 14-22 carbon atoms;
Z.sub.1 is a water-soluble monobasic or polybasic anion;
d and d.sub.1 are independently 0-6; q is 0 or 1; f.sub.1 is 1, 2 or 3; p is 1-3; and p+q.gtoreq.2.
The mixture of the soft-rinsing agent (a) and (b) constitutes from 10 to 25% by weight of the composition at ratios of (a):(b) of from 1:9 to 9:1. The alkyl groups in R.sup.7 and R.sup.9 are preferably completely saturated. Viscosity control agents, including electrolyte salts, e.g., calcium chloride, may be included.
U.S. Pat. No. 4,724,089 to Ko/ nig, et al. discloses aqueous dispersions of certain amines, including reaction products of higher fatty acids with a polyamine (e.g., ##STR7## where R.sub.1 =acyclic ali-phatic C.sub.15 -C.sub.21 hydrocarbon; R.sub.2 and R.sub.3 =divalent C.sub.1 -C.sub.3 alkylene groups) with a dispersing aid (e.g., HCl) and, optionally, quaternary ammonium salt (e.g., diamido (alkoxylated) quaternary ammonium salts). Relatively small amounts of electrolyte, e.g., CaCl.sub.2, can be added to adjust viscosity.
EP 0295,386 to Ruback, et al. discloses a free-flowing softening washing rinse concentrate containing (a) from 18 to 50 weight percent of a mixture of at least two quaternary ammonium salts: (A) 10-90 wt % of triethanol-amine ester quaternary ammonium compound, and (B) 90 to 10 wt % of another quaternary compound including quaterized amidoamine (or equivalent esteramine or thioamine) and (b) water and optional conventional additives.
While these and many other proposals are known for improved fabric softening compositions, nevertheless, still further improvements are desired.
One such proposal is described by Schramm, et al. in the commonly assigned, copending application Ser. No. 07/995,102, filed Dec. 22, 1992. According to this proposal stable, aqueous, pourable and water dispersible, fabric softener compositions which include (A) a fabric softening effective amount of an inorganic or organic acid salt of a finely divided softening compound of formula (I): ##STR8## wherein R.sub.1 and R.sub.2, independently, represent C.sub.12 to C.sub.2 O alkyl or alkenyl; R.sub.3 represents (CH.sub.2 CH.sub.2 O).sub.p H, CH.sub.3 or H; n and m are each a number of from 1 to 5; and p is a number of from 1 to 10; (B) a dispersant stabilizing effective amount of a dispersant having the formula ( II ) , (III ) , (IV) or (V): ##STR9## wherein,
R.sub.4 represents a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.5 represents a hydrocarbon group having from 1 to 22 carbon atoms,
R.sub.6 represents C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
R.sub.7 represents C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
R.sub.8 and R.sub.9 each, independently represent a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.10 represents a hydrocarbon group having from 8 to 22 carbon atoms,
R.sub.11 represents a hydrocarbon group having from 1 to 22 carbon atoms which may have an hydroxyl group substituent,
R.sub.12 and R.sub.13, independently, represent C.sub.1 -C.sub.4 alkyl or hydroxyalkyl,
Z represents a divalent alkylene group of from 1 to 6 carbon atoms, or an hydroxyl substituted alkylene group;
R.sub.14 represents a hydrocarbon group having from 8 to 22 carbon atoms;
R.sub.15 represents a hydrogen atom or C.sub.1 -C.sub.4 alkyl or hydroxyalkyl; and
(C) an aqueous solvent, were provided as ready-to-use products or as concentrates to be used at reduced levels or which may be diluted with water prior to use at the same or similar levels as the ready-to-use products. In the ready-to-use composition the total amount of amidoamine softener (A) and stabilizing dispersant (B) is disclosed to fall in the range of from about 2 to 8% by weight. In the concentrated form the total amount of (A) and (B) is generally in the range of from about 12 to 60% and may be diluted at ratios of water:concentrate as high as about 4:1 to even 8:1 or 9:1, and still provide acceptable softening performance, equivalent or better than that achieved using conventional quaternary cationic surfactant softeners, such as dimethyl distearyl ammonium chloride (DMDSAC).
An alternative embodiment of the Schramm, Jr., et al. fabric softener aqueous liquid compositions which is adaptable for use in the rinse cycle of a laundering process and which is described as stable, pourable, and dispersible in water, includes the following ingredients:
The compositions disclosed in the aforesaid application Ser. No. 07/995,102 of Schramm, Jr., et al. provide highly effective stable and pourable liquid fabric softener compositions; nevertheless, in practice it is found that with concentrations of the amidoamine fabric softening compound (e.g. Varisoft 510) in excess of 11 weight percent in the presence of certain emulsifiers, such as hydrogenated tallow, the product viscosity becomes excessively high, even in the presence of electrolytes (e.g. CaCl.sub.2) or solvents (e.g. propanol). While higher total concentrations of the amidoamine were achieved using the soft tallow product Varisoft 512 or mixtures of Varisoft 512 and hard tallow product, Varisoft 510, the softening performance of the Varisoft 512 containing compositions, presumably due to the lack of hydrogen bonding sites on the protonated soft tallow compound, was not sufficiently improved.
Ways to increase the concentration in the liquid fabric softening composition of the amidoamine softener compound varisoft 510 in view of the very good environmental attributes and favorable acute toxicity data of this compound and its strong softening performance are desired. However, as noted above, at high concentrations the viscosity increases substantially until gelation occurs.
James and Ogden (Journal of the American Oil Chemist's Society 56 1979) describe that the viscosity of aqueous cationic dispersions is highly affected by the manufacturing variables such as the temperature of the dispersion, electrolyte content, and method of stirring. Not only the dimension and speed of the stirrer but also the stirring time and the size and construction of the mixing tank influence the fineness of the dispersion. They also point out that dispersions of low viscosity can be produced directly by homogenization.
It was recently discovered that the incorporation of cyclic imidazolinium compounds can increase the concentratability of fatty amido tertiary amine softeners and also significantly improve the softening efficacy of Varisoft 510. This discovery is described in greater detail in the commonly assigned copending application Ser. No. 08/065,207, filed May, 20, 1993 (IR 5206/17). According to this copending application a stable, pourable, water dispersible aqueous liquid fabric softener composition includes:
(A) a softening effective amount of an inorganic or organic acid salt of a finely divided fatty amido tertiary amine compound of formula (I): ##STR10## wherein R.sub.1 and R.sub.2, independently, represent C.sub.12 to C.sub.20 alkyl or alkenyl; R.sub.3 represents (CH.sub.2 CH.sub.2 O).sub.p H, CH.sub.3 or H; T represents O or NH; n and m are each, independently, a number of 1 to 5; and p is a number of from 1 to 10; (B) a viscosity controlling and softening improving effective amount of a cyclic imidazolinium compound of formula (II): ##STR11## wherein each R represents C.sub.12 to C.sub.20 alkyl or alkenyl;
T represents O or NH; and
X represents a counter-anion of valence n'; and
(C) an aqueous solvent including an anti-gelling effective amount of electrolyte. Compositions containing up to 25 wt % of active ingredients (A) and (B) are exemplified, with amounts of (A) and (B) up to 60% being disclosed.
Notwithstanding the various improvements in formulating concentrated aqueous liquid fabric softening compositions suitable for use as rinse cycle softeners still further improvements are desired for such compositions containing at least 25 weight percent of cationic softeners with respect to one or more of the following properties: low viscosity (e.g., below about 2,000 cps at 20.degree. C. and preferably below about 1,500 cps), stability against phase separation for extended periods, stability against increasing. viscosity over extended periods, improved softening performance and rapid dispersibility of the composition when added to water, including cold, warm or hot rinse water. Furthermore, it is desired to achieve these higher concentrations (to reduce packaging costs, etc.) in still pourable liquid compositions without requiring high pressure homogenization or emulsifying agents which do not otherwise contribute to softening performance. Still another important consideration is the softening performance of the composition in hard water as well as soft water.
Accordingly, it is an object of this invention to provide low viscosity, stable and flowable aqueous dispersions containing high concentrations of environmentally acceptable fabric softeners to provide enhanced softening performance.
Another object of the invention is to provide such low viscosity, stable and flowable aqueous dispersions With nitrogen compound fabric softeners in amounts of at least 25 percent by weight of the composition and which. are suitable for use with or without further dilution to provide softening performance at least equivalent to that obtainable with present commercially available rinse cycle fabric softeners.